The present disclosure describes a system for copying an optical channel in an optical communications system. More specifically, the present system describes a special kind of four-wave mixing element which enables dynamic copying of single or multiple channels.
Fiber optic cable has the capability of carrying an enormous amount of information. Demand for bandwidth in long distance communication lines is growing rapidly because of applications like the Internet.
To accommodate this bandwidth growth, commercial fiber optic systems now employ wavelength division multiplexing "WDM" in which information is carried on many optical wavelengths spanning a wide optical bandwidth. Each wavelength is called a channel and can carry substantial amounts of information.
It may be desirable at some times to copy the information in one channel or a subset of channels.
For example, in applications such as next-generation-Internet, a fiber optical cable will carry multiple wavelengths and use packet switching techniques. Reading header information on a packet, for example, could require a device that can copy the channel which contains the packet. Once copied to a specific wavelength in the optical spectrum, the information can be conveniently filtered using a fixed wavelength filter and then read (i.e., detected). Clearly, it is important for the copying process to be non destructive.